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How does Zinc work?

Zinc is needed for the proper growth and maintenance of the human body. Zinc is needed for immune function, wound healing, blood clotting, thyroid function, and much more.

Are there safety concerns?

Zinc is safe for most adults when applied to the skin, or when taken by mouth in amounts not larger than 40 mg per day for adults age 19 and older. Routine zinc supplementation is not recommended without the advice of a healthcare professional. In some people zinc might cause nausea, vomiting, diarrhea, metallic taste, kidney and stomach damage, and other side effects. Using zinc on broken skin may cause burning, stinging, itching, and tingling.

Taking more than 100 mg of supplemental zinc daily or taking supplemental zinc for 10 or more years doubles the risk of developing prostate cancer. There is also concern that taking large amounts of a multivitamin plus a separate zinc supplement increases the chance of dying from prostate cancer.

Taking 450 mg or more of zinc daily can cause problems with blood iron. Single doses of 10-30 grams of zinc can be fatal.

Some research suggests that zinc nose spray may be unsafe. It may cause loss of ability to smell. Until more is known, avoid using zinc nose spray (Zicam, Cold-Eeze).

Zinc is also safe for most pregnant and breast-feeding women when used in the recommended daily amounts (RDA). Pregnant women age 19 to 50 should not take more than 40 mg of zinc per day; pregnant women age 14 to 18 should not take more than 34 mg per day. Breast-feeding women age 19 to 50 should not take more than 40 mg of zinc per day; breast-feeding women age 14 to 18 should not take more than 34 mg per day. Premature births and stillborn infants have been born to women who took 100 mg of zinc three times a day during their third trimester of pregnancy.